Volatile anaesthetic vaporising apparatus



Dec. 1, 1959 w. EDMoNDsoN ETAI- 2,915,061

VOLTILE ANAESTHETIC VAPORISING APPARATUS Filed Nov. 25, 1957 UniteStates Patent VOLATILE AN AESTHETIC VAI ORISING APPARATUS WilliamEdmondson, Oxenhope, Keighley, and Wilfred Jones, Long Lee, Keighley,England, assignors to Cyprane Limited, Haworth, England, a Britishcompany Application November 25, 1957, Serial No. 698,525

Claims priority, application Great Britain December 24, 1956 11 Claims.(Cl. 12S- 188) This invention relates to apparatus for mixing the vapourof a volatile anaesthetic with a gaseous fluid such as air, oxygen ornitrous oxide, or a combination thereof7 al1 of which for convenienceare hereafter included in the term gas Various types of apparatus of theabove kind have been produced and this invention is concerned withapparatus wherein gas can be passed straight through to ank outlet or aportion of the gas passed through the vaporizer so that a percentage ofthe volatile anaesthetic is added to the out-flowing gas. Hithertodifficulties have been experienced in providing said apparatus withVeicient and simplecontrol means for regulating the flow of a gas andvapour mixture and the main object of this invention is to provide meansfor solving this problem.

According to the present invention there is provided Vaporizingapparatus for a volatile anaesthetic, including a valve housing having amain gas inlet and a main gasvapour outlet with a valve controlledby-pass passageway therebetween, a gas inlet from the housing to avolatile anaesthetic vaporizing chamber with a temperature controlledvapour outlet from chamber to housing, the latter inlet and outlet beingnormally closed when the bypass valve is fully opened and automaticallyopened by partial closure of said valve by manual control means to anadjustable gas-Vapour regulating position, said control means beingadapted to provide further adjustment of the valve towards the fullyclosed position for reducing theamount of by-pass gas and increasing thepercentage of vapon'sed anaesthetic.

The invention provides vaporizing apparatus for a volatile anaesthetic,including a body casing to contain volatile anaesthetic which canvaporize in at least one chamber in the casing, a gas inlet to and a gasoutlet from the casing, temperature controlled valve means forcontrolling the passage of gas-vapour mixture from said chamber to saidoutlet, a manual control valve associated With graduated scale means fornormally closing said inlet and outlet and having an inner headed partfor controlling the bypass ow of gas from a main inlet to a main outlet,the arrangement being such that initial axial displacement of the manualcontrol valve partially closes the-byfpass passage for gas and uncoversthe inlet to and outlet from the casing and further infinitely variableaxial displacement between predetermined limits controls the relativeproportions of by-pass gas and gas fiowing to the Vaporizing chamber.

The invention includes apparatus wherein the manual control valvecomprises a piston-type member mounted to rotate about its own axis andhave simultaneous longitudinal displacement when operated manually, saidmember having annular ports for the inlet of vaporizing gas to thecasing and outlet of vapour therefrom. vSaid valve member may also beformed to act as pressure balancing means between the casing and theatmosphere.

The control valve member is preferably constructed to be axiallyadjustable in relation to its manual operating means for settingpurposes.

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The accompanying drawing illustrates an embodiment of the invention in asectional view which will now be referred to:

The improved apparatus includes a body casing 1 for containing volatileanaesthetic and is furnished in its bottom region with a horizontallyprojecting hollow inlet body 2 for the introduction of a liquidanaesthetic. Preferably this inlet tube is constructed so that with thebody casing 1 in a vertical position only a given quantity ofanaesthetic can be introduced into the casing. As shown the inlet body 2has a funnel-shaped top 3 leading to a screw-threaded passage 4 with alateral opening 5 in register with a hole 6 in the wall of the casing 1.A removable plug 7 has its partly screw-threaded stem 8 entered into thepassage 4 for the plug to make a metal to metal joint with the seating9. Anaesthetic can be poured into the liller body 2 up to say the level10 which showing in the mouth of the passage 4 is a ready tell-tale ofthe liquid level in the casing 1. Too much liquid anaesthetic cannot bepoured into the casing 1 as it could not rise above the level 10a as itwould spill over the lip of the top 3.

The casing is also furnished with a viewing window l1 in its wall toenable the level of the liquid to be seen. at will and also a drainingplug device 12, cock or valve, is furnished in the bottom of the casing.

The casing 1 contains a plurality of cylindrical wicks 13 of differentdiameters carried concentrically by the casing wall and perforated orother supporting means 14 and so'arranged that liquid can be raised intoa series of vaporizing chambers by capillary action. The arrangement issuch that in elfect vapour from the liquid anaesthetic rises into theupper region of the casing and converges inwardly into a central chamber15 to pass out through an outlet passage 16 connecting with the top ofthe casing. The inlet port 17 to this outlet passage is controlled byadjustablevalve means 18 carried by a temperature sensitive element 19mounted within the casing. For example, said element is a bi-metallicstrip secured at its lower end to a pendant arm 20 having the.

aforesaid inlet port 17 formed in the upper part thereof and said arm iscarried by a mounting member 21 which carries some of the wicksupporting means 14 and has the aforesaid outlet passage 16 formedtherein.

The above body casing 1 has a valve body 22 mounted on its top to form acylinder for a piston-type horizontal valve member 23 which is a neatworking t in the cylinder bore. At one end of the cylinder bore, withinthe valve body, is a communicating chamber 24 into which the inner sternend 25 of the valve member normally projects for its enlarged valve head'Z6 to control the flow of gas which enters laterally through a maininlet opening 27 into the valve body through the chamber 24 and then outthrough an enlarged gas-vapour outlet 28 to which any suitableconnection may be made. rl`he gas inlet enters into the open enlargedend 29 of the valve cylinder bore to flow round the said valve stem 25and into the chamber 24, and a spring 30 bearing against the valve head26 urges the valve member towards its normal open position.. Through thewall of this valve cylinder is provided a gas auxiliary inlet passage 31into the body casing 1 and parallel therewith is a vapour auxiliaryoutlet passage 32 in register withV the aforesaid outlet passage 16 inthe casing. Annular ports 33, 34 are provided in the valve member 23,and the stem 25 in effect forms a port between the member and the head26, for said ports to register with the said inlet and outlet passagesin the valve cylinder. A vapour duct 35 longitudinally in the valve bodyleads to the outlet 28 from a point adjacent the vapour outlet 32 andsaid duct is communicated with outlet 32 when annular port 34 is inregister therewith as shown. v

The outer end of the aforesaid valve member has an operating sleeve 36secured thereon and such sleeve is furnished with a milled or othergripping knob 37 which enables the valve member to be rotated about itsaxis and given axial displacement. To give initial longitudinaldisplacement to the valve member 23 and further axial displacement whenit is rotated, the sleeve is furnished with an annular cam groove 38into which there is entered a pin 39 secured in the valve body 22. Thecam groove has a longitudinal straight part 38a and continues in apart-helical form, This sleeve is also furnished with a graduatedindicator disc 40 which rotates in relation to a fixed pointer 41, orthe like, secured to the valve body.

Conveniently the valve member also serves for controlling the pressurewithin the body casing 1 and thus acts as pressure balancing means. Theport 33 cornmunicates through a hole and an axial passage 42 in thevalve member with a space in the aforesaid operating sleeve 36 and fromthence through a small orifice 43 in the sleeve to atmosphere. Thus whenthe valve member is in its inward or vapour olf position for the throughpassage of gas, the annular port 33 will be in register with the gasinlet passage 31 to the body casing which will thus be in communicationwith the atmosphere for balancing the pressure in the casing. It will beappreciated that should there be an increase in temperature which wouldraise the pressure in the casing due to an increase in the vapourpressure there will be automatic relief to atmosphere through theaforesaid means.

The operation of the above apparatus is as follows: In the firstinstance the manual control valve is in what may be termed the olfposition with the head 26 of the valve at its furthest open point awayfrom the open end 29 of the valve cylinder bore and the two aforesaidinlet and outlet passages 31, 32 in the valve cylinder body 22 coveredby piston parts of the valve member, i.e. shut off from the inlet 27 andoutlet 28. In this position of the valve the casing 1 will only beconnected to atmosphere by means of the port 33 and passage 42aforesaid. Moreover, the operating knob 37 will be in its innermostposition with the fixed guide pin 39 lying at the forward end of thestraight part 38a of the cam groove 38. With the valve in this positionall gas entering the apparatus by inlet 27 will be by-passed throughchamber 24 to the main gas-vapour outlet 28. To bring the vaporizer intoaction the operating knob 37 is drawn axially outwards until the pin 39reaches the start of the spiral portion of the cam groove 38. At thispoint the aforesaid inlet and outlet passages 31, 32 to and from thecasing 1 have been completely uncovered so that gas entering theapparatus can either be by-passed to the main outlet 28 or through inlet31 into the vaporizer casing. In this manner the proportion of gas beingby-passed straight to the main outlet 28 is controlled by the valve head26 and the proportion of gas-vapour leaving the casing 1 throughpassages 16 and 32 is controlled by the aforesaid temperature controlledvalve means 18. The operating knob 37 can now be rotated and as thelixed pin 39 is in the spiral cam groove 38 there will be correspondingaxial displacement of the valve member head 26 towards the open end ofthe cylinder bore which will gradually reduce the amount of gas beingby-passed to the main outlet 28 and increase the amount of gas beingpassed into the casing l for vaporizing volatile anaesthetic and thisconsequently results in a stronger mixture through the aforesaid mainoutlet 28.

Dealing now with the calibrations associated with the valve knob 37, themarking olf on the disc 40 can be used to indicate when the valve head26 is in its extreme open position to show that the gas is not beingallowed to ow to the vaporizing chamber 1. When the knob is pulled outinitially it reaches the point when rotary calibration takes place andthe disc can have any suitable graduation marking to show that this isthe percentage at which vapour mixture will pass from the ap- 4 v 1paratus. Preferably, the position of the valve member 23 for this startof rotary calibration is made axially adjustable so that the valve headposition can be set by a manufacturer or service engineer to give adesired starting percentage of mixture. Conveniently, the end 44 of thevalve member is screw-threaded to engage with internal screw-threads inthe knob sleeve 36 and have an end slot 45 for the introduction of ascrewdriver. By means of such a tool the valve member can be given axialdisplacement in relation to the knob and its sleeve to set the positionof the valve head 26 and the adjustable setting retained by tighteningup the grub screw 46. To prevent interference a anged ferrule 47, whichalso serves to ihold the knob on its sleeve, is screwed into the end ofthe sleeve 36. A cap or other closure member 48 is used to close theopen end of the knob. In this manner the screw setting of the valvemember in relation to its operating knob decides the initial lowpercentage setting and the slope or angle of the spiral groove 38, whichmay be of a pitch, or combination of pitches, to suit the calibrationrequired, decides the range above this point. By providing thisadjustment the vaporizing apparatus can be made to suit different typesof volatile anaesthetic.

It will be understood the apparatus may be modified without departingfrom the scope of the invention and particularly the body casing 1 andits interior tments may be constructed to suit requirements. Ifdesirable, instead of using multi-wick means 13 a single cylindrical orother wick may be employed.

What we claim is:

1. Apparatus for vaporizing a volatile anaesthetic comprising a valvebody having a main gas inlet, a main gasvapor outlet, and a by-passpassageway providing communication between said main inlet and said mainoutlet, said valve body having also in a wall thereof an auxiliary inletand an auxiliary outlet each in communication at one end with saidby-pass passageway, a lirst valve member movable in said valve body forcontrolling the passage of fluid through said by-pass passageway andalso the openings of said auxiliary inlet and said auxiliary outlet, acasing secured to said valve body, said casing having at least onevolatile anaesthetic vaporizing chamber therein and rst and secondpassage means providing communication between said vaporizing chamberand said valve body auxiliary inlet and outlet, respectively, secondvalve means in one of said casing passages for controlling the passageof fluid therethrough, temperature-responsive means iforadjusting theopening of said second valve means as a function of temperature, andmanual control means for progressively displacing said valve member withrespect to said valve body to simultaneously open said valve bodyauxiliary inlet and said auxiliary outlet and to progressively close thecommunication through said by-pass passageway between said main gasinlet and said main gas-vapor outlet whereby the percentage of vaporizedanaesthetic delivered from the body main outlet is increased.

2.. Vaporizing apparatus as defined in claim 1 wherein said first valvemember comprises a piston-type element having longitudinally spacedannular ports therein adapted to cooperate with the openings of saidvalve body auxiliary inlet and auxiliary outlet, said valve member beingmounted for rotation about its longitudinal axis and also for axialmovement relative to said housing.

3. Apparatus as defined in claim 2 wherein said lrst valve member has areduced stem portion projecting axially at one end thereof, said sternportion terminating in a valve head adapted to cooperate with a valveseat in the valve body for progressively closing the by-pass passagewaybetween said valve body main inlet and said main outlet.

4. Apparatus as delined in claim 3 wherein said valve body by-passpassageway constitutes a cylindrical bore within said valve body, saidfirst valve member stem portion extending through a portion of saidcylindrical bore 5 i v and said valve head having a diameter larger thanthe diameter of the cylindrical bore.

v5. Apparatus as dened in claim 2 wherein said manual control means isadjustably connected to one end of said first valve member by means ofan operating sleeve screwthreadably connected thereto.

6. Apparatus as defined in claim 5 wherein said operating sleeve has acam-shaped groove inthe outer periphery thereof of part-helical and partstraight conguration, said valve body having a stationary pin engagingsaid camshaped groove so that the sleeve and the iirst valve member canbe initially displaced axially and then rotated relative to the valvebody to achieve controlled axial adjustment.

7. Apparatus as deiined in claim 2 and further including spring meansnormally biasing said iirst valve member to -fully open said by-passpassageway and to close the auxiliary inlet and auxiliary outletpassages.

8. Apparatus as dened in claim 2 wherein said rst valve member includesa venting passage for venting to atmosphere said auxiliary inlet openingand thus said volatile anaesthetic vaporizing chamber when said valvemember is in its normal fully open position.

9. Apparatus as dened in claim l wherein said casing includes aplurality of concentrically-arranged tubular wicks disposed verticallytherein, said casing second passage means being centrally located withrespect to said tubular wicks.

l0. Apparatus as defined in claim 1 and further including iller meansmounted in the wall of said casing through which a given quantity ofanaesthetic may be introduced into said vaporizing chamber.

11. Apparatus as defined in claim 10 wherein said filler means comprisesa ller body connected to the wall or" said casing, said filler bodyhaving an internally screwthreaded inlet opening providing communicationwith the interior of said casing, and a plug screwed into said openingto make a joint with a seating, said ller body having a funnel-shapedentry to said opening.

Great Britain Jan. 3, 1951 Great Britain Oct. l0, 1956

